Buggy code:
public class ImgReaderNodeModel < T extends RealType < T > & NativeType < T > > extends NodeModel implements BufferedDataTableHolder { public static class CombinedIterable < E > implements Iterable < E > { private final Iterable < E > [ ] m_iterables ; public CombinedIterable ( final Iterable < E > ... iterables ) { } @ SuppressWarnings ( "unchecked" ) @ Override public Iterator < E > iterator ( ) { } } private final SettingsModelBoolean m_checkFileFormat = ImgReaderSettingsModels . createCheckFileFormatModel ( ) ; private final SettingsModelBoolean m_completePathRowKey = ImgReaderSettingsModels . createCompletePathRowKeyModel ( ) ; private BufferedDataTable m_data ; private final SettingsModelString m_filenameColumn = ImgReaderSettingsModels . createFilenameColumnModel ( ) ; private final SettingsModelStringArray m_files = ImgReaderSettingsModels . createFileListModel ( ) ; private final SettingsModelBoolean m_isGroupFiles = ImgReaderSettingsModels . createIsGroupFilesModel ( ) ; private final SettingsModelSubsetSelection m_planeSelect = ImgReaderSettingsModels . createPlaneSelectionModel ( ) ; private final SettingsModelString m_imgFactory = ImgReaderSettingsModels . createImgFactoryModel ( ) ; private SettingsModelBoolean m_readAllSeries = ImgReaderSettingsModels . createReadAllSeriesModel ( ) ; private final SettingsModelIntegerBounded m_seriesSelection = ImgReaderSettingsModels . createSeriesSelectionModel ( ) ; private final SettingsModelString m_metadataModeModel = ImgReaderSettingsModels . createMetaDataModeModel ( ) ; private final SettingsModelBoolean m_readAllMetaDataModel = ImgReaderSettingsModels . createReadAllMetaDataModel ( ) ; private final Collection < SettingsModel > m_settingsCollection ; private MetadataMode m_metadataMode ; public ImgReaderNodeModel ( ) { } @ Override protected DataTableSpec [ ] configure ( final DataTableSpec [ ] inSpecs ) throws InvalidSettingsException { m_metadataMode = EnumUtils . valueForName ( m_metadataModeModel . getStringValue ( ) , MetadataMode . values ( ) ) ; final ReadFileImgTable < T > tab = new ReadFileImgTable < T > ( m_metadataMode ) ; String column = m_filenameColumn . getStringValue ( ) ; <START_BUG> if ( ( column != null ) && ( ! ( column . equals ( "" ) ) ) ) { <END_BUG> if ( ( inSpecs [ 0 ] ) == null ) { throw new InvalidSettingsException ( "Optional<seq2seq4repair_space>input<seq2seq4repair_space>is<seq2seq4repair_space>configured<seq2seq4repair_space>but<seq2seq4repair_space>disconected" ) ; } if ( ! ( inSpecs [ 0 ] . containsName ( m_filenameColumn . getStringValue ( ) ) ) ) { throw new InvalidSettingsException ( ( ( "The<seq2seq4repair_space>configured<seq2seq4repair_space>column:<seq2seq4repair_space>'" + ( m_filenameColumn . getStringValue ( ) ) ) + "'<seq2seq4repair_space>is<seq2seq4repair_space>no<seq2seq4repair_space>longer<seq2seq4repair_space>avaiable!" ) ) ; } } return new DataTableSpec [ ] { tab . getDataTableSpec ( ) } ; } @ SuppressWarnings ( "unchecked" ) @ Override protected BufferedDataTable [ ] execute ( final BufferedDataTable [ ] inData , final ExecutionContext exec ) throws Exception { } @ Override public BufferedDataTable [ ] getInternalTables ( ) { } @ Override protected void loadInternals ( final File nodeInternDir , final ExecutionMonitor exec ) throws IOException , CanceledExecutionException { } @ Override public void reset ( ) { } @ Override protected void saveInternals ( final File nodeInternDir , final ExecutionMonitor exec ) throws IOException , CanceledExecutionException { } @ Override protected void loadValidatedSettingsFrom ( final NodeSettingsRO settings ) throws InvalidSettingsException { } @ Override protected void saveSettingsTo ( final NodeSettingsWO settings ) { } @ Override protected void validateSettings ( final NodeSettingsRO settings ) throws InvalidSettingsException { } @ Override public void setInternalTables ( final BufferedDataTable [ ] tables ) { } }

Fix:
if ( ( ( column != null ) && ( ! ( column . equals ( "" ) ) ) ) && ( ! ( column . equals ( "URL" ) ) ) ) {